Assigsob



INDIVIDUAL SWITCH IIIECIIAIIISIII FOI? AUTOMATIC TLPHONE SYSI'EIVIS Immed May 20. IIIIQ.

SIIEETSVSHEEI' 3.

o\ II.

A. E. KEITH.

INDIVIDUAL SWITCH MECHANTSNI FOR AUTOMATIC TELEPHONE SYSTEMSv APPLTcATmN FILED APR.29, mns.. REA-:Evan: Aus. 15,1914f SHEETSWSHEET 4 A, E, KEHH. INDIVIDUAL swlcH'v/IECHAMSM FDR AUTUMANC TELEPHONE SYSTEMS.

APPLICATION FILED APR.29. |905- RENEWED AUG. 15,1914.

PMS-@med MEW 20, 19m.

mmm-SHEET 5.

A. E: KEITH. TNoTvTouAL swTTcH MECHANTSM Ton AUTOMATIC TELEPHONE SYSTEMS.

APPLICATION FRED APR '29 i90' RENWD AUG. 15.1914. 1,304,324. Y

A. E. KEITH. INDIVIDUAL SWITCH MECHANISM FOR AUTOMATIC TELE PHONE SYSTEMS. APPLICATION FILED APR, 29, |905'. II-ENEWEII AUG. I 5. I s I 4.

1,304,324, Famed my 20, 1919.

SHEETS--SHEET Y.

ill? XTR@ ALEXANDER E. KEITH, O3? CHICAGO, LLNS, ASSIGN'R, BY MESNE ASSKGIVENTS,

TO AUTOMATIC ELECTRIC CQll/ENY ,fav

Application led April 29, 1905, Serial No. 258,026.

llo it known that l, ALEXANDER E, ilici'rii, u citizon o'l tho linitoil Stains of America, :nul resido-nt of Chi :iiginCook `county, lilinois` have invontod n, certain new and usolul lmpi-iwomont in lndividl'lal.S\vitoh lvlorlmnism for Automatic Telephone Systems, oi which the following; is :i Spooiliczition.

My invention relatos to automatic tolo phone systems in general, hut more portico lnrly to uulonmtic telephone systems o that general typo in which uitonintio switches are olnployoil in pince of the woll-known minuut] switohhimrds, incl eSpeoially to :iuftonmtic telephone systems of that character in which tho connections between Subscribers lines uro brought about. by tho culling subscrihors through the medium of switchw` 01* switching nntchinos which operato on the stop-l ystop principlo-lzhnt is, switches or switching machines provided with circuitolonini; inounss adapted fori'nnking' any ono ol :t nunrbor of possible connections. and in which :my particular or desired Connection in lnfought about in o step-l y-stop Inunnor unil in rosponso izo onobr moro electrical ini-- pulsosl trnnsniiltful ovor 'the lino-(1irouii,|7` from. tho calling siii s :i'il oi"s station. ln or;- clmngos of this groiuinl ohzuzuftor, tho nurnher of swilclws or switching nnrchiiuaiI nooo Snrily elnployoil lay :my ontllinp;l Sulrcrihoi in osmhlishing; tho ilosirvil connection rv ponds, of coni-soi, upon tho ssizo :nul oupiuf, of 'rho oxohuiurn, if. rf.. 'lhu iuunhor ol? ouh scrihers having; linof toiimiimingf :it tho zo chungo or control station. For omniplr. tho exchange muy hu o? suoli Siiio that the milling suhsorihor' will iitefwmi'ily employ' c, Wirst soloctoi", :i sommi oiool'or :nul :i oonnhc-- tory in nio/kino' tho ilomrod oonnocl ion, whii-h would lio tho (fuso il1 tho nuiuhor oi tl o rnllofl suhscrihor contuinml i'our iliggii: 'out :is will hereinafter moro 'fully zippmriz. :i louis nunihor fi'l switches will ho oinployoil hy n vulling; Mihsorihor ilE tho number of tho ullml sul scribor contains hut two Cligiizx. 'ihn Ho* mllel first .solool'orsi nro ihho swim-luis or switching;f mau-limos whioh roooivr-r thv ifm'- roni-impulso or iini'iulfiof-s roiiircsonlim ilux first (lilit of the iulloil nui'nhog whiheI llul sowrzllml soconfl-solottors" im* liu' zwilrhw or swi'irhingg nuuhinns which i'iwuvi lhl vurr'vntfiimuilno or impulsws i'opnlsonlinir ilu n wills wvoncl digit ol thiE coll ,wl minimi: i.

Specification of .'Letters Patent'.

HHS.

Renewed August l5, 1915i. kerio No. @56,9%3.

nootor7 hovvoif'm', is 'tho switch or switching machine-which .receives mui, responds to the electrical impulse or imouloos representing' the lost two digits, of the oziilocl number, :nul which malins the ntil oonnootion (liront-ly `with the line of the @filled subscriber, In the .S3/stom to which my invoiition more pairticuhirly relates, zi solootor5 Whether it. be lirst, second, third, ifo' Z-h, oto., is profoilably so constructed that it con ho controlled. directly by the calling` subscriber for picking ont a, portiouior group of trunk-lines; hut after boing thun operatori by the calling?,l subscrihon it thon conso@ to he under the conn trol of the calling subscribe-r, :ind proceeds automatically to piel; anti establish oonnection with tho liist, ,irllo trnnloline which it finals or .encounters during its nutonmtio noarch, so to speak, through tho Suid group of'trunlz-linos. ln thin Way, one or moro "soleotors con. ho employed a, calling sub- Horiher in ostiihlishihgg connection with u, connector and the latter con then he; om- ,oloyeil 'for i'iioking' out ond making Connection with tho lino of the culled Subscriber; but ho connector is. during; its operation, always under tho Control of tho calling' suhsorihoz', sind dono not only rosponfl to tho milling suhsorihois; ,mts .for tho purpose, of picking out tho i'iznftioulzir :froup of sul `Sorihos limes; in which tho czillocl nubsorihors lino is included. but', ohio thon performs :inothoi oporntion which 'in strictly in accorti- :ftnfso with tho Switching' operation zu, tho Calling suhsvrihoff@ ,a ion, unil 'for tho purposo ol picking' oui' i pm'iffulor or mooi Suhsvrihors lino with which tho smiling suhiirilwr ilosi'os to i t-fillinh commotion. firul in mich umso, il will o louis-,rumori thm', tho Stop-hy-stop opor mi ol' o .iohotorl or ofi i; uinlnovior"` i liroiught about or inil'iul'oil by tho l'mnsinisesion ol ono oi* moro olorli'ioul impulsos in tho lino-circuit", tho wolliinowu uri'n 'n ji'flnoni hn' this purpose consisting of suhsorilun'es muitoliingi ilviceo hy which n nmkovzinilhrozil iulion muy' ho proiiuzoil nt will in :i gii'onntioil lino-circuit in*l Chilling: tho lino-rolujifH oi tho particular swiluh or switching inuhno which tho nllino enlist-fion is ooorzitziinz.

ln zx systfnn oi ihis liinil, unil prior lo tho invontion th'esoriluul in my :ipi'ilii-,iition Sorn! No. 229,3?5.) i'iloil l-ot'ouu' 2L Gli/l, it haul :slwuys boon ouslonmry7 whore it wos (hsir iilfhe or hoifo-ssiurv to trunk to di'orom, huw

.can be considerably le:

tired-groups of connectors, according to lle Character of the called number, to i, wide a irst-seleclor for each subscriber-e line-- that is, to provide a number of inist-selec to;1 corresponding in number to the total number of subscribers, and to then ari-ain the other Seleotorsf i.' any were employed, and also the connectorga on porcellini; l basis-allait to Say, irl euch manner tlv the total number oli' seeonteeieotoi example, would be one-tnith ot the number of subscribers., In olhei' wor had been customary, where it was nece or desirable to provide means for trani; to different Groups of connectors, te provide each subsci'ilies line with a Fn'v'itching inaehine `whieh recoiveifl number-impulses from the sub-,station to which it was allottedr` and which i as nSed by that particular' subscriber and no others; and with such arrangement it is evident that an exchange will include a quantity of switching machines correyspending in number to the total number of as that oi any other machine in the exchange. y' In my said prior application, however, li`

provide each enlisorihers line with an *'nth viclual-mviteh which ia never called upon lo respond to ninnber-inipnlses. and whi" subjected to a minimum oi' wear and forthis i'oaaon;--narnely that it anto cally picks out an idle trunk-line lea-ding a first-Selector, and loes so in a` very oa and comparatively simple manner, en.; il' never called upon to respond 'to more than. a Single impulee. In thie way, a compara- 'lively small ainoun, and )An'aically min4 nnun amount, of work is ab' lgned to the switches which are individual to the dili'or ent subscribers, and consequently the Selectors, as, for example the firer lect-,on i

numb z' total ninnbor ol submenu-wg and n a` switches or switching; inaehineeA whii-,h af" Called upon to respond lo nu iieiwin'iiuileee, thus arranged on a pereenage basis. il ie evident that the imiividnal-swi'ehes may be characterized by the simplest and moet economical construction and mode of operation.;for in p 'actice l Find that ellicient servlce can be given the subscribersl by employing only ten trunk-lines to eaeh individualsWitch-that-ie-ito say, by making' it necessary For ein-h'` individual-switch7 to aulo matioally Search, through ,only ten ironielines in order to find one which is idle and in condition .for use by the 'ailing subsm'il'iei'. Tit/h l'he old ai'iinigzemenly1 involving a limit selector for each Snbam'iheWe line., ily is evi-- dont that in a large exchange each ii'atland niaiiitenanee oi.: the o f niasmneh as each nidi mal( n' connection with.

l bandi-gd trani-alinea, thei'eby eesaiy for each C" t-eelee ,i ont the desired group of ten ii 'to then peiionn another onnation nera lio Y and and hipglily eiiicient ind me einem .for nee in automat systeme of the iforegoi y reduce tia v be of a vompalatively sim #t1-nomina and eharacei Switeln to do anythingx more logo the connection which nl waiting; for it. and to thiny malte the d onne 'ion without resortingV to an legi movononle` unil withonl resin enrolling operatioin "for an all alla` Snii'il l whiley lhe, switch was idle.

finoihri' object is lo gn'o'i'ido an imi` Conalzin'lion and arrangl'einonl olI :aan i acier' that i'ho indiviilnal-awieh i opel-ated by :l yJingle vlwli'ix'al impulse iii-o Iiowloil over lho lino by Home aii on ila" pari ol' the walling' suhsvrilwi, hul whivh iiignilae is not a preliminary impulse ai: 'liar as, itu lio-- ingy liansini'l'ed prior to and indent ol he entire 'ailing operar-ion ia eenmr'nei although it is a in'eliir' Senso laat it necesaa cirfxni for tile pui'pi liinimxljiVy ranno-` with an and hel'ol'e the initial actuation may al functions of 'actuatinn' the Upossibleto operate both the selector or other switch or switching mal chine picked out by the individual-switch and employed for receiving the impulse or .impulses representing the `first digit of the called ninnber, and for .performing the necessary switching operation vcorresponding to i 'j device at t e'subscribers station.

A.- further object is to provide an improved construction and arrangement of such character as will obviate the necessity of providingany wipers-or other traveling switchcontacts, and as will permitall of the different possible connections which the indi-4 vidual-switch is capable of-makin to be accomplished through the medium ot a plurality of springfswitclies each complete in itself and provided 4with all contacts necessary for making the connection for which it is employed, only the means for operating the different spring-switches, ample, as a key or plunger of insulating ma teriah'being common to all of saidhspringswitches, and consequently to all of the'different trunk-lines leading from the individual-switch but vthere being no necessity, with this arrangement, of employing wipercords and wipersl which travel fromone positionto another for 1the purpose of making a connection here or there, as the case may be.

Another object is to provide an'. improved construction and' arrangement involving a mechanical bridge-cutof adapted automati- .I cally to disconnect the line-relay of the individual-switch as soon as the latter is fao.

`mal or initial position after it has succes-- thrown into an operated position-#that is,' a position necessary for establishing any one of the different possible connections.

A further object is toprovide an im@ proved construction and arrangement wherey the idle trunk-selecting means will quickly -and automatically return to its norsively put into use each of the trunk-lines allottedl to the individual-switch, and.

whereby said means will then be in condition to again search among the same set of trunk-lilie-terminals for an idle trunklinc, the search each time being first among those truiik-linc-teriniinils which were rst put lin use and which would, therefore, be

most likely to be disengaged and out of use.

-normal or idle of such individualswitch will be thrown 7 initially gers-or keys of the other or idle into use, the idle plunger-s or keys are moved such, for eX- y Another object is the provision oi' iinproyed -ineans for clamping the magnet-coils inv position and for readily ailj'usting the same.L i

A further object isto provide an improved construction and arrangement of such character that when lthe parts of an individual-switch are returned to their positions, the key or plunger into line with vthe like plungers or keys of fall lother idle individualswitches, and thus brought into position to engage an idle set of trunk-line bank-springs or trunkterminal-springs as soon as the subscriber to whom the individual-switch i is allotted sends in another call, the arrangement being such that when-one or two or three of .theI individual-switches are in use, so that one or two or three or any other number of 4the trunk-lines are occupied, the plunindividualswitches ,y are all in line, and such that as lfast as the trunk-lines are occupied or 'put to a position opposite the next idle trunk line., thus always making it possible for a calling subscriber to accomplish the desired preliminary connection lwith a' trunk-line without moving his individual switch from the 'position in which he finds it when he starts to make the call.

'It is also an object to providecertain details and features of improvement, and certain featuresv of construction, tending to increase the general efiiciency of an automatic telephone system of tliis'p'articular character.l

.Tothe foregoing and other useful ends my invention consists in the matters hereinafter set forth and claimed.

In the accompanying drawings, Figure l is a' plan of'two io'ilmy improved individual-switches, showing a section of the shaft which is common to all of the individualswitches iin the particular group to which` U0 those shown belong, and showing also the` step-by-step mechanism which is common to all of said switches,'and which is employed `foi' rotating said shaft.

Fig.i2 is a section on line 2 2 in *i showing the autoinaticstep-by-step r( taping mechanism i'n end elevation.v A

y v Fig. 3 is a detail view of the wiper-"and Aladjacent parts ofthe automatic stepbystep.

mechanism. 1

i' Fig. 4 is a detail perspective showing the contactsand the end of the arm for inter nupting the currentl which energizesthe magnet employed for .producing the step-by-step 1 Fig. 6 is a section on line '(-.Gin Fig. 1,

showing one of the individual-switches in M19 side elevation, and in its normal position, the main Shaft and certain other parte being shown in Section. v

Figs. 7, 8 and 9 are detail views oit certain portions` of the f :ontact-banlrs olf 'the individual-switch.

Fig. l() in a detail sectional View of one or" the contact-banks oi: the individualswitch, showing the plnngere or keys 'in engagement with the Flexible or movable circuit closing springel of the said banks.

Figfll is a View siinilar to 10, but Showing the said pllingjera` or l ys with drawn and ont of engagement; with the Switcl'rsprings ofthe bank.

l2 is a, cliagrainiuati" View showing the operating circuits oi" the individualswitch, and showing the circuits ,of the Stepvby-etep mechanism for rotating the switch-shaft.

Fig. 13 in a f liagrannnatio View illustrating the method of multi plhving together the bank-contacts et the individual-en'itchee, and of connecting` the saine to the bank-contacte of the step-by-step nieclianisin for rom tatingthe Shaft.

Fig. 111- is a. diagrannnatic View Showing a calling` Subecribers line connected with a called Subscribers line, and Showing thc connection established through the medium oi an individual-sivitchd and a connect/oi,

.it being assumed for convenience, of illustration and description that -the exchange is of Such Size that Selcctore-, either tiret, second, third, etc., are not necessary in .making; connection between any two Subscribers lines.

p Fig.` l5 is a diagrammatic View showing the circuits and operative parts of a Well known and Well understood forni of conn nector.

Referring to Figs. l to 5, Will be seen that the switch-operating inachine, or sep-by-step mechanism for operating the switclrshaft "i, eoniprisee a pair of rotary-magnets 2 and a rotary-relay 3, all oi Said electro-inagnets being preterably supported upon an arin or bracket 4. secured to the rack-bar 5. This bar 5, together with the other raolebar 6, constitutes the means for Supporting the individ ual-rswitchei,"n and the Switch-operating machine, it being understood that all of the individualewitches and their Switch-operating machine can upon a suitable rack. The shaft l is preferably Supported in a horizontal position by means of a bearing 7 at one end`r and by means of a Suitable bearing at its other end, it being observed that the V id ividualswitches are distributed alonef the length of said Shaft-that is, along` the length ot that portion of the eha'ttfnf'hich in composed of the angle-iron or l shaped piece S. `it

le provided with a its' euch the said shelf inclusive, it

be removably mounted' clock-spring device il, of any .suitable or de sired character, for .i'ieldingly holdingl it in its normal poe ion, and for automatically returning it to its normal position when released alter traveling` around to the limit oi? its step-b3 p rotary motion. As illust ed, the sain shaft is provided with a Wiper or n'iovahlc switch-ann 10 adapted to cooperate with the Set ot contacts` arranged in a single ro in the bank l1. ltwill be seen that this; henk comprises teu contacts l2, arranged in a Semi-circle about a horizontal axis coincident with the Shaft 1, and that these contacts are zn'rangcd upon one Side olf a strip of insulation 18.. while a contiinioin` .contact-plate 1.4i is positioned at the oppoe te side thereof. The ten contacts are provided with terminals l5, and the Said contactplate with a terminal 16a. The Wiper l() preferably lii'turcated at'itS end,` so that it may not only slide around. upon the Said contaetplate 14, but may also Swing around and trayel from one contact to the next. Th contacta arealliihenlated from, each otheil and from the Said contactplate, and are preferably clanu'ied between two metal plates` il" and held together by means of Sere 1S. The means for coniinunicating inet-ion ,troni the rotar-)enragnets 2 to the Shaft consist of an armature lipivoted at E20 an? `'angeged just above the :said inap-net., e f

/ r with a cani 2l on the said short, a ratchet-wheel having pins adapted to engage the Said cani, and a spring pawl Q4 mounted upon the Said armature and adapted to engage the Said ratchet-wheel. lt will he Seen that the ro- 'taryniagnetel eiracured to a bracket Q5.

which latter ini v2S adapted to be held normally in engage ment with the bracket '135 by the tension oil the si'iring Q6. it wil be seen that the Screw or adjneting device Q7. i'or regulating' the tension of the spring QG ieecrewed into the bii'aclret 25. The pan'l 2451's piyoted at 29 to the arn'i or end portion 30 carried by the Said armature. A spring 3l. connected at one endwith the rear end of said paWl, and at its other end portion. constitutes the means for yieldinly preeeinfl` 'the said pawl into engagement With the teeth of the ratf'rhet-Wheel 2Q. The seid armature iS limited in its movement a 'troni rotaryinagnet7 by the engrV nient o? the arin Q8 with the bracket Q5, i in its movement .iard the said magna'A with the said arln 0r end` Cit lco

'32, also carried by vto its norn'ia'l position.

vthrough the cam 2l by the emgagement of the interruptor-arm the armature, with the 'stationary stop 33, the latter being carried by the iuackct-platc 4. This interrupterarm 3Q provided with an end portion 34 adapted to open and close the switch-springs 35 and 3(5,the latter being normally in engagen'lent with each other, and suitably secured tothe bracket-plate 4 by means of screws 37. These switch-springs and 36 are arranged at either side oi an intermediate or operating-spring 38, it being observed that both of said switch-springs have their outer ends bent laterally to provide end portions located at opposite sides oi.' the operating-spring 38.l A piece of insulation 39, secured to the latter from engaging or making electrical Acontact 'with the spring 38. The laterallyprojecting end portion 34 of the' interruptor-arm is adapted to engage the end portion of the spring 38, and When the armature is attracted this end portion 34 then bearsl upon the end portion of the `spring 35, and then slips olf from the same and engages the spring 38. rllhis separates the springs 35 and 36, and Whenthe armature is released the portion 34 then travelsback between ther spring 38 and the end portion nl the spring 35, thus insuring va complete separation of the springs 35 and 35 until the armature is fully retracted or restored armature igsuiiicient to move the ratchetwheel one tooth each time it is attracted,

it being' observed that the arm or stop ,33 pawl 24 into engage-A is adapted to guide the ment with the ratchet-teeth. A locking-dog 40, mounted on the bracket 4 and controlled by a spring 41, engages the ratchet-Wheel 2Q and prevents back rotation of the latter. lt will be seen that the cam 21 has a. curved or concave cam surface 42 adapted to be engaged by the pins 23 on the ratchet-Wheel. ln Fig. 2, the mechanism if' shown in its normal condition-that is, with the Wiper 10 on the first contact of the bank ll, and,

the cam 21 in engagement With one of the pins 23. When the rotary-magnets are energized, the single step imparted tb the ratchet mechanism will be comnmnicated to-the arm-or wiper l0, the movement being just suflicient to carry the wiper from the .Erst to the second contact. ln this Way, cach energizing impulse rereived by the rotary-magnet brings about a rotary step on the part ofthe. ratchet mechanism, and consequently another step on the part of the switch-wiper 10. It Will be seen that the cam is so shaped thatr its end or point is disengaged from the pin as soonas the 4wiper 10 disengages the last conta-.t in the bank,y thus pemnitting the clock-spring device 9 to restore the shaft 1 and all parts operated thereby to their spring 36, h prevents thev The stroke of the normal or starting point positions. As soon as the cam 2l is disengaged from one ofl part of stant motion in one direction on the part of the ratchet mechanism serves to alternately operate and release the -Wiper l0, thereby giving the latter a back and forth movement over the contacts. It Will be seen, however, that the forward movement of the Wiper 10 is yof a positive nature, as it is brought about by the positive actuation of the ratchet mechanism, While the return or ack movement of the said Wiper is automatic and brought about by a spring after its disengagement from the operating mechanism. In this Way, the Wi er 1.0 has a comparatively slow or stepy-step movement in a forward direction, but has a quick retnrnmovement. As shown, the relay 3 has an armature 43 which is pivotally mounted at 44 and provided With van arm. 45. This arm is provided at its end with a piece of insulation 46 adapted to operate the normally-separated switch-springs 47. When the relay is energized, its armature closes these springs 47, as Will hereinafter more fully appear. y

Referring more particularly to Figs. l and 6 to 11, inclusive, the construction of each indivdual-switch is preferably as follows: Each individual-switch, as thus illustrated,l vcomprises a line-relay 48 composed ot' tvvoA suitably connected electro-magnets arranged in a horizontal-position' one. above the other. The cores ,49 of the said relay-magnets are of sufficient length to eX- tend through openings in the vertical fiange 50 carried by the body-frame site sides of this vertical flange are arranged the bowed or sprung straps 52 and 53, the same being provided with end portions having openings adapted to receive the cores of the said relay-magnets. In other words, the said straps are arranged flatwise uponand at opposite sides of the-said flange, and in such position that their openings register with' the openings in the lange, so that the relay- 11o- 51. At oppoi magnet-cores project through the three super- A imposed thicknesses of metal.v At the center or' the three thicknesses-of metal thusV arranged latwise together, plied in such manner that the said flange andthe strap 53, bu't'has its threaded end portion in threaded engagement with a threaded opening in the strap 52. Obviously, with this arrangement, a tightening ofthe said screw tends to produce a screw 54 is ap- 1t turns loosely in '125 :in eudwise or leng 'eni movement on 'the part of the two straps thereby causing the seine te poeh ,ei clamp the cores tightly against the outer su is olf openings in the flange-that isj a tightening of the screw tends to produce a shearing notion, thereby clamping the cores in pince. it will be seen that the said screw caribe loosened, thereby loosening the cores in their peniiigs7V and thus permittingv the ielaij-inagiiets to be easily and accurately aqueted The so called release-magnet '55, consisting ot' two electro-magnets. secured to a. flange 56 in a, similar manner. In ense, the straps 57 and 58, together with the screw 59, eonstitute the inea-ns for clamping and holding;l the end portions 60 of the inagiieteores. This release-magnet is provided with an armature 51 which is pivoted :it/62, so that it may swing about :i horizontal' exis, end thus be operated by the lower end of the said ielease-niagiiet."` The said armature is provided with a relatively short arm 63 adapted to be engaged hy a spring 64u. :ein other spring Gli, itwill he seen, is coiled around the pin G5, and 'thence around the pivot oi' 66 provided for the plungeiwl erin 67. The end portion of said sl'iring is then `eqipliefl to this arm 67 in siieh manner that it tends to depress the right-hand end portiow'of the said arm. ln this way, the

spring 64 serves as thenieans for holding the armature 6l iiorn'iallji7 :iwan from the lower end of the i'elease-inagiiet, and for depressing the longer end portion of `the pliingernrm 67 when the letter is released by the armature-latch or release-link 68. It will be seen that this hitch or release-link 68I provided atits upper end with a hook 69' adapted to slide upwardly noon the lefthaud end of the iii-in (i7, hut so iorined that it cannot he drnrwn downward without then engaging the said :ii-iu and drawing the latter into its normal position. At 7U the said latohor release-link pivotally secured to thel armature G1. lt will also be seen that the said latch or release-link is provided at its lower end with an erin 71 adapted to be engaged by a spring 72 carried oy the seid arn'xature. In' this way, the spring 72 permits the latch. or release-link 68 to @wingl ontwardly for the purpose of either disengaging the erin 67, or of rising into positionjto engage and draw 'the seid arni into its normal position. As shown, the said lateh or release-link G8 serves as`the armature for the lline--i'elay. Ll8-tliat is' when the said line-relay is energized it attracts this' latch oi' release-link and thereoriY releases the keys 74 and 75, the saine plunger-erin (i7. Thev said plunger-erin is rovid'ed et its end with a, pivoted plunger 3. The end portion of this', ililunger is provided with two 'pointed switelnplnngcre or honig pi'e'lrralili' ol" herd rubber or other iusiileting mad-rial.

The upper end portion of the plunger 73 'is adapted to i't the holleny or concave side of lthe angle-iron 8, whieh latter, it will be borne in minda e, part oi! the switch-shaft l. In conjunction with this plunger, the individuiil-switch comprises a bank 76 of spring-contacts adapted to loe operated by the pointed end portions of the said plunger. These contacts are, it will. be seen, arranged vin two rows, the contacte in one row being ""line-eontaots,7 and those in the other row being contacte for closing circuit through the iotei'v-rela l 3 and also throufh the with the continuous contact-platos 7 8 and 7 9. i It will be readily understood that these spring-contacts are all suitably iusuhtted from each other, aiid'from the said contactpiates, and thatthe latter are insulated :troni each other. The plunger-point is adapted to engage and operate aniv one of teu pairs of spring-contacts 80, and to push the .saine into engagement with the continuous `contact-plates 8l and 82.1 Fig. 7 is a perspective of a portion of pne'of said contact-plates, and Fig. 8 is a perspective of one or' said spiing-contaets or switch-springs; and in Fig. 9, which is a View looking;r down into :i portion of the bank, it will be seen that each pair of spi'iiigcontacts or switch-springs presents a, socket-like appeiirance, the ends ol the springs being so formed as to accurately receive and nido the plunger-points in the right direction. It will he seen that eaeli of the flexible spring-contacts of the benk is provided at its rear end with a 'terminal wherebyY it may be soldered or otherwise couneeted to a eircuit-wire. Each of the two continuous contact-plates is also provided with a suitable terminal, as shown in Fi". 7. As stated, the flexible spring-Contacts of eachv ro are arranged in pairs between the two contact-plates allotted to such row, and with the arrangement shown the contacts and intei-posed strips of insulation are all cuirnped tightly together by means of oppositely. iii'- i'enged and vertically-disposed elnnipiug'- plates 83 zuid 84 and by means of elan'ipingscrews 85. 1With this arrangement, the plii'n ger 7? is adapted. when the arm 67is released, to be forced by the spring (il into engzigeincnt with two pairs of spring-contines in the two rows in the hank., thus simuh aiiecnsljv closing sev-eral circuits in the mennef' hereinafter inorifull explained. The

ioe

- bridge-cut-oi-relay 86 is arranged in ahorizontal position and secured by a screw `87 to a bracket 88, the latter bein suitably Secured to the side portion of t e frame 51. An armature 89 is provided for the said bridge-cutoff-relay, .said armature bein pivotally mounted upon the bracket 88. In this Way, the said armature has a horizontal axis 90 at the oint Where it is pivotally connected with t e said bracket. In addition, the said armature is provided. With yan arm 91, and with a pieceof insulation 92 mounted at the end thereof. lThe normally-closed switch-springs 93 and 94 are arranged one above the other and, together With suitable strips of interposed insulation, secured to the' top `of the bracket 88 by means of screws 95. In this Way, the armature 89, when attracted, causes the insulation-921m press the spring 93'nut of engagement Withthe spring 94. In tis conrection, it will also be seen that the .plungerlarm 67 has its shorter'end portion provided with a nger 96 having a piece of insulation 97 adapted, when the said arm 67 is'released, to, engage and raise .the spring 93 out/.of engagement with the `spring 94. Consequently, the bridge-cutso springs 93 and 94 are adapted to be operated either by the relaymagnet 86, or by the vline-relay 48, -as will hereinafter more fully appear .in connection with a description of ,the circuits tem. In Ja Way, they are alsooperated by the re1ease-magnet.55, inasmuch as the energizing and denergizing of this magnet effects a restorationof:thelaiim''jto its nor mal position, andthereby "areclosing of the. and ,by be seen said springs 93 and 94. y In practice, referring to Figs. 12 and 13, 1t will y that the subscribers line-wires are connected 82 of one roW in the bank which comprises the springcontacts 80and which is, p

the pairs of spring-contacts between the two plates trunk-line.

contacts-the member which is adapted to.

i make contact with the grounded plate-is connected with one "of the contacts 15 of u i w the stepbystep mechanism; but'the other member of each .pair-that is, the member adaptedrto makey contact with the plate whichis connected with thefirelease-magnet.is connected with therelease trunkline-conductorynf line leadi'g'frft springor switch-s corresponding switchelectro-ma.gne.=.t=-J and the 'switch-Springs opof such connectorl `bridge-cut-off-relay 86 to contact corresponding to the and operation of thel sys-1 l done 1n the usual to the two contact-plates represented bv theffner. In Fig. 2 the conductors 81 and struction, for the in fact, bank 76 (Fig'j), While are each connected with a different',

Also, it will be seen that oney of the plates in the other row 1s connectedeorresp'ondino: trunk- V l) the bank 7 6. ocketiri the other row. Itri-Willbe understood that all the ditl'erent crafted thereby, are provided'with suitable terminals for" making the necessary circuitl connections therewith. I y

As shown in Fig. 1,4, the calling subscribers line-Wires 98 andI 99 extendydirectly to the contact-plates 81 and 82, while the 100 and 101 lead di.

trunk-lineconduetors rectly from the sixth vpair c f springs 80 to the condensers, 102 and 103 in the connes# tor shownmole in detail in Fig. 15. As previously stated, the iii-st trunk-line selected by a calling subscriber can lead to a irst-selecto1, second-selector, etc., ac-

co'rding to the size of the exchange; or, if

the exchangev is comparatively small, the,A

said trunk-line may lead directly to a com nector as illustrated in Fig. 14. Referring to Figs. l2 and 14, it will be seen that the so-called 104 and 105 lead from the calling subscribers line, and may ybe vassumed to be connected with the vertical and rotary bank-con tacts of an ordinary connector,` whereby the calling subscribers line may be called by som-e other subscriber through themedium On the other hand, the so-called private-normal 10G leads from one terminal v`of. the calli-'ng subscriber-s the 1jivate-bankwith which the normals 104 and 105 are con? nected inthe said connector4 by winch the ine-contacts vertical and rotary normals calling subscribers line is called bysome other subscriber. Inother Words, the calling subscriber at station A calls outthrough the medium of his individual-switch and receives aV call through the medium of the l Which the said normals 10i, 105 and 106 are connected;.and this is and Well understood manplate 14 is shown proyided,.vvith a terminal 16.

sake ofV simplicity, which will accon'iplisli the same end, is represented in Fig. 12. In the same figure the "yviper 10 is provided with aterminal 16 which is, in fact, theterminal 16 Shown in Fig. '2. .It vvillv be understood that when I say that in Fig. 12 the terminal 16 of the contact-plate in bank 11 is connected with one terminal of' the rotary-relayI 3, I mean that the Wiper 10 takes the place of plate 1.4, "and thatthe bank 11 is r -A different con-I xpresented by the Vollta'ts "12 therefore, the .non-grounded pole of-tlre bat-v as leading directly to the said f i .e Plate-79111 Onthey other hand, howeven.`

the plate 4.78)insaid bank is connected with .Y

the battery through the release-magnet Normally, the nongrounded pole' of the battery is connected through the coils of the line-relay L1S, and

tlirough the normally-closed contacts 93 and 94 with the vertical-lirie-conductor 98 of the calling subscribe1"s`line.- From the nongrounded pole of said battery-a normallyopen circuit leads tln'ough the coilof the rotary-magnet 2, through the normally-closed interrupter-springs and 36, and thencer through the normally-open relay-springs 47 t ground at 110, and thence from ground 108 to battery. l

It will be readily understood that the other switches or switching machines cniployed in the system may be of any suitable, known or approved construction. For eX- ample, the connector shown in Fig. 14 as the medium 'through which the selected trunk-line is connected 'with the called subscribers line, may' be of the `Well-known form and construction shown in Fig. 15. This connector 'of the forni or type shown in Patent No. 815,176, ygiantf-:d March 13, 1906, to Keith, Erickson Se Erickson, and will not need extensive description. As

illustrated in Fig. `15the said connector comprises the usual switch shafty 111 mounted for both rotary and endwise stepby-step movements, and provided with the usual private-Wiper7 112, and also with the line-Wipers 113 and 114. These. wipers cal and rotary` magnets lare adapted to operate the switch-shaft through the me-y dium of the usual ratchet or step-by-step devices, While the said private-magnet is adapted to operatejthe side-sWitch-Wipers 125, 126, 127 and 128 in the usual and wellunderstood manner. As is customary in a fconnector of this character, a ringer-relay 129 isprovided for enabling the calling subscriber to connect the calledsubscribers line with the ringing-generator 4130 after the connector has established the desired connection. The details of construction may be of the character fully shown and described in said patent,` achthe'rcharacter of the eircuits and the operation of the different dey vices shown in Fig.' 15 Will be more easily and better. understood 1n connectlon with the hereinafter descrilwd operation of connerting` the calling subscriber@ line with the called subscriber-s line.

The subscribers apparatus, both for talkii'lgand signaling, and also for calling or performing the `itching operatioiis which bring about the actuation of the individual and other automatic switches at the ccntral station or exchange, may be of any suitable, known or approved character'. In vFig. 14, the calling subscribens apparatus A is the same as' the called subscribers apparatus B, and consequently a description of the former lwill suffice 'for both. The apparatus at sub-station A comprises a suitable transmitter 131 arranged in a normally-open local circuit includinga local battery 132 and one winding 133 of theusual inductioncoil; This local battery circuit for the transmitter i'naintained in a. ,normallyopen condition by the normally-separated switch-springs 131- and 135, the latter being adapted to be operated by the insulation 136 carried bythe switch-hook 137. The receiver 138 v.has one terminal connected with the switch-contact 139 of the calllngswitchkey 140, while the other terminal of said receiver is connected `through a normally-open.' connection with the switch-contactr 141 of the caflhng switch-key 142; it being observed that this connection includes the normallyclosed switch-contacts 143, and the normally-open switch-contzu-ts 11H, and also the other winding 145 of the said inductioncoil. The key or button 116 has another contact 147 with which it is normally out of engagement. This contact 111-7 is vptnm'anently connected with the two contacts 148 and 149 of the calling switch-keys 140 and 112, and also with the normally-disengagcd switch-spring 150, as well as with the; normally-disengaged switch-spring 151.v The switch-hook provided with a piece of insulation for operating the springs 151 and 153. the latter being ,f nounded at 154. The said switch-hook is also provided with a metal portion 155 adapted to normally engage the Spring 156 and thereby normally connect the bell 157 in bridge across the' slibscribers line. .A portionI 158 carried by the switch-hook, and insulated therefrom, is eniployed for operating the spring-contact 159, and for thereby press-ing the three springs 159, 160 and 15() together whcnthe receiver is replaced"upon the heeley The construction is such, however, that when the receiver is removed, and theswitchrhook rises, these three springs operatedby the projcctioh 158 are not pressed together. is also of such character that whenI thefho'ol,`

The'.construction j is depressed it closes together the said )three springs` before, opening-er i separatingfthe. y*

springs 151 and 153i.. As will hereinafter ISU aannam.

calling the desired number, while the button or key 146 can be employed for ringing the bell at the called subscribers station. The three springs 159, 160 and 1 50, however, are employed merely for the purpose of eitecting the automatic release of the switches' along the line-circirit as soon as the ,calling subscriber hangs, upxhlis receiver.

The manlerofigsing the apparatus lthus shown, and"thc method of connectingthe calling subscriber@ line with the called subscribers line, are as ffollows: The subscriber `at station A removes the receiver from the switch-hook 137, thereby closing the local circuit of the transmitter, 'and also closing the connection from ground 154 to the switch-points 148 and 149. After this, the

said subscriber presses the switch-key 142,

the required number of times, according to the character of the firstdigit of the called subscribersnumber. VThis 'completes a grounded circuit from ground' 154 through the -contact 149 and the. vertical-line-conductor 98,`through the springs 93 and 94 ofthe bridgefcut-of-relay of the subscribers individuallswitch, through the line-relaycoils 48, fand thence to the non-grounded pole of the battery 107. The said linerelay-coils, when thus energized, cause their 'thereby efecta withdrawal of the armaturecatch 69- from the end of the plunger-arm i 67. When this is done, the spring 64 presses cores to' attract thearmatuie 68, and t'o the plunger 73 into engagement withlthe contacts in the bank 76. As the two pointed ends of the plunger enter the' bank, four connections are established; first, the linesv 98 and 99 leading .from the calling sub ond plunger-point also closes the circuit from ground at 109 to the bank-multiplewire 164 leading to the bank-contact 12a of the shaft-rotating mechanism. 'The wiper 10 of the said shaft-rotating mechanism is always in lin'ewith the idle plungers of the different individual-switches-that is, the master switch wiper 10 is always maintained in engagement "with the bank contact 12 which corresponds to the individual switch bank opposite which all idle plungers are resting, and since the bank contact 12a is allotted to the bank terminaljust seized by the'plunger 7 3, the wiper 10 will be resting u on this particular contact at this time.

onsequently, a circuit will be closed from ground at 109 through the banlosprings to the .conductor 164, through bank-contact with which wiper 10 is engaged, wiper 10,

conductor 166 and rotaryd'elay4 3 to the non-grounded pole of the battery. As the armature of relay is attracted, -it closes circuit from ground 110 through the inter-` rupter springs 35 and 36, and through rotary magnet 2te the non-grounded pole of the battery. This having been accomplished,

the said rotary-magnet is immediately energized, and `in attracting its armature causes the main shaft, through the medium of the ratchet mechanism, to make another step, thus carrying the wiper 10 to the next adjacent contact. The said'wiper will remain upon this latter contact, providing, of course,

that this contact does not correspondv to a trunk-line which is already in use; for insuch case this contact would be connected to ground, and the circuit being thus maintained through the rotary-magnet, the step-bystep mechanism will be continued in operation `until the wiper arrives at a nonbusy contact. 0bviously,y however, and while l all this is'happening, several other things have occurred. ,For example, as the plunger-arm 67 was released, .the arm 96 caused the insulation 97 to engage the spring 93, thereby separating this 'spring from the spring 94, vand thus opening the circuit through the line-relay 48.' In this-way, the calling subscribers line-circuit is made 4free from bridges; and in addition 'the re' 'leasing of the plunger-arm 67 is laccomplished so quickly that a portion of thelirst or initial impulse 'transmitted over the linecircuit by the calling device is communicated to the Verticaltrunk-line-conductor 100, 'and thence-on to, the next switch, the latter in this way being practically operated by the samc'monientary grllnding of the subscribers line at the sub-station.. In other words, the ,fiirst number-impulse projected onto the line-circuit by the calling subscriber is s uilicitnt to operate both tlie-individualsswitcli and give the next switch, as, for exmnple, the connector, the desired operation'm accordance with the first, impulse necessary for producing the operation cor' responding to the first digit of the called number. ln this way, it is only necessary for the calling subscriber to start the calling operation, inasmuch as the first `impulse incident to the operation of the calling device is I sufficient to operate the individualfswitch and therebymake the preliminary connection necessary for putting the subscribers line in communication with the switch to be employed for performing an operation core responding to the `irst digit of tl1e..called number. After getting connection with the next switch, as, for example, a, firstse* lector or a cc mi1eCtor"-aconnector being shown in the drawings-the calling subscriber can then operate his calling device in such manner as to produce the desired operation on the part of the said connector.

The restoration of the switches may be accomplished in the usual manner-that is to say, simply by hanging up theI receiver at the calling subscribers station. This, of course, grounds both sides of the line at the sub-station, and thereby energizes the two line-relays 117 'and 118 of the connector. This having been accomplished, the springs 168 are brought together', thereby connecting the connector to ground at 169, and thus allording a circuit from the grounded pole of the battery through the connector, back through the conductor 161, through the bank-springs held together by the plunger-point 74, through the release-magnet 55, and through the conductor 163 to the' non-grounded pole of the battery. The said release-magnet, being thus energized, attracts its armature 61, thereby causing the upper end portion 69 of the armature 68 to engage the end of the arm G7. As soon as the magnet is denergized, the springl 64a'then retracts the armature 61, and in so doing causes the armature 68 to pull the arm 67 into its normal position. lVhen thus re'- stored to its normal position, the arm 67 causes the plunger 7 3 to engage the portion 8 of the shaft 1, So as to bring the said plunger immediately into line with all other idle plungers of the different individualswitches. In this way, the restoration of an individual-switch is accompanied by a selective action on the part of its plunger, providing, of course, that -the said shaft 1 has been rotated to a different position during the time that the plunger 73 was in use.

Then another subscriber calls the line ruiming to station A, it is evident that the connector employed for so doing'completes a lcircuit from ground 170 through the "sideswitch-wiper 126, through the private-wiper 112, thence through one of the bank-contacts 115 over the privatenormal 106, through the bridge-cutoffrelay 86, and thence to the nong'rounded pole of the battery by way of the conductor 163. In this Way, the bridge including the line-relay 48 is opened up or cut ofil when a subscriber' calls the sub-station A,A as 'well as when' a subscriber at this station attempts to call some other subscriber. In one case the bridge-cut-oll vis operated electrically by the energizing of the bridgecutoffrelayeoil, while in theI other ease it is operated mechani .ally by the releasing of the plungerarm 67. This is shown in Fig. 14, whereit will be seen that the bridgc--cu-t-olfrelay 86 de'e ero' d, thefl'iridge-cut-olf beingl held open fb insulation' carried by the 6?; "individualswitchf al.

lotted 'to the called subscriloers line, the bridge-cut-of-relay 171 iS energized., therebyY opening the bridge across the circuit including the line-relay 172. With this arrangement, the normally bridged line-relay ot' an individual-switch is advantageously gotten rid of each time the subscriber calls or is called.

The manner of operating the connector, and of ringing the bell at thecalled subscribers station, Will be readily understood, and will need no detailed explanation. The subscribers calling device can be of any suitable character; but as shown, the key 142 is employed for operating the individual-- switch, and for operating the vert-icalrelay of the connector. The key 140 is employed for energizing the so-called rotary-relays of the selectors or of the connector, as the case may be, and for thereby operating the sideswitch l of the selector 7 and the connector,7 in the usual and well-known manner. lVth the arrange-- ment shown, for example, the operation of the key 142 brings about the desired automatic operation on the part of the individual-switch, and also produces the requisite or desired vertical step-by-step movement on the part of the switch-shaft 111 ofthe connector. A single impulse then transmitted by means of the key 140 over the other side of the circuit, energizes the r0tary-relay 118, and thereby accomplishes a closing of the local or internal circuit including the privateanagnet 123. This, of course, gives the side-switch l one forward step-from the first to second position-and puts the connector in position to receive the next impulse or impulses transmitted by the key 142. This time, however, the impulse or impulses transmitted over the so-called vertical-.line-conductor ofthe circuit brings about the energizing of the d rotary-magnet 122, the sideswitelllaim 125 having been shifted into positiontto close circuit at this point Ythrough the said rotary-magnet. 1n this Way, the calling subscriber rotates the shaft 111 until the wipers thereon arrive at the contacts corresponding to the line oi the called subscriber. After this, the single impulse transmitted by the key 140 ell-ents the final move ment of the side-switch from second to third position, Athus estal'ilishing connection between a trunk-line and the called subscribers line.

The means for transmitting the impulses which correspond to the number of the 'called subscriber, and which accomplish the' desired operations on the part ol the individual and other switches, is called a calling device tor' the reason that it is employed by the calling subscriber tor electrically calling the number ci? the other subscribcr The bell. ich schets r1 neeeeee course, u` call signal, but these end the pushbuttons or switches for operating theni ere distinguished lrolnI the calling devices 'by referencethereto es the means for ringing the culled subscriber.

' l lt Will be seen that eech subscriber lies control of his particular or allotted individuel-switch for connective purposes onlywthut is, he cannot bringr about any se" lectivo action on the part oi his individuelswitch. Euch subscriber is, however, given means whereby he ymay cause his individuah switch to close the connection Which it has lxeady selected, end whereby he may et 'the "time cause all idle ,y indiyidueh t of his particular group, to select .the'neiitddle trunk-line. ln this wey, each v subscribernlways finds his individualswitch ready and 'in position to establish connection with an idle trunk-line, provid ing, of course, that all of' the trunlnlines itl lotted to et group of subscribers ore not busy et the seine time. Each subscriber hes con- "trol over his particular individuel-switch for conn ctive purposes, end in eddition lues control over all idle individualisteitehes,

other than his own, 'o selective purposes only. Consequently, each subscriber is given :in individuel-switch of such character that it een quickly malle the desired gore liminury connection Without resorting to any selective operation or searching through the different trunk-lines, and ofsuch cherecter that, when put in use, it eutoineticellyand instantly causes the switch-operating machine to produce e, selective operation on the port ofell idle 'individuedswitoheif7 in the same group. i "With this errengement, no subscriber een use his indiyidu:il-switch 4f Without automatically advancing ell idle individuel-switches .in the suine group te e position where each is ready to respond stantly to its allotted subscriber for the )our-r pose of establishing connection `with :in idle trunleline. By thus iorovhf euch suhscriher 'with en indiyiduel-s` which is alive-ys ready end in Condit, e, wheL lthe subscriber desires to cell some other subscriber, to establish connection with e pre viousl'y selected idle trunk-line, it is evident ythat the first nu1nber-irnpulse transmitted by the calling device, or that the tiret im pulse brought about by the initial nioveinent or operation of the calling device, is :imply sufiieient to operate both the individueh switch :ind the select-01" or connector or other switch next in line Jfor operation. ln. other words, the individuel-switch cenhe operated by the first number-impulse intended for producingl the initial operation ofy :i selectorf connector7 or other siniiler rswitch, und without in uny wey interfering with the necessary or desired operation on the port ot' the lutter. fflhviously, the initial impulse, or first numherimpulse es it muy the ceiling; subscriber@ Station is O enedA v the selector or connector or other switch next in line for operation, and for which the impulse is llso intended, is in electrical communication with the calling; subscribers line, and is given the desired actuation or initial operation by the flow of current through the new circuit established from the non-grounded pole oit the battery through the selector or connecten or other switch, over one side of the trunk-line end through the liice-contects7 oli the indi \\'iduul-switoh, and thence over one side of the subscriberls line to the ground connection which is still closed. lVhen en indiriduel-suf'itch@is released, its plunger will simply withdrew :troni engagement with the particular.benlceontects en'iployed for inch:-A ingF the connection, and will return to norinul engagement with the shaft 8, whereby the plunger 73 is automatically placed in the suine selective position es the remain ing idle plungers. lin this wey, the release oli eech "individuel-switch is accompanied by the automatic selection on the port of its plunger ci. another trunleline, and of e, trunlf-line which is, el course, idle or out of use et the time the release is made. Preferebly, and with the arrangement shown, euch plunger is, when released from its bank of contacts, eutonieticelly brought into eline meut with all plungers which are idle et thu-t time. ln this Way, the idle plungers in the group always occupy the seine switching position, and we made to edfvence'in unison f :troni one switching position to unother es fest es the diilierent individuehswitches ure successiwly put into use. lt' there are' fifty subscribers in the groen, it is evident that; only ten oft these subscribers een use their indiyidiuLl-switehes77 et the same time; but in p notice l find that for ten subscribers to be using their individual switches et the suine time is not likely to occur, and that it is even possible to include one hundred subscribers in a group hey/ing out ten which their individuel-switches may be employed tor gettingr connection With a lirst-selector7 or connector7 or other switch, us the cese muy be. lf there are one hundred subscribers in the group, and five subscribers are using their individuel-l switohes at the suine time, it is evident that the plunger-s ol these five switches will all occupy dil'erent switching positions, so that euch subscriber muy have u dierent outgoing trunk-line g but it is lsise evident that the remaining ninety five Y i lle nulli/iti switches will all lieve t r piungers l up and held in the seine switching position by reason et their engagement with. the `elilerly-shapeel portion 8 ef the shaft l Should n wither snhseriber eleeiclo' use his individnzil-switeli, the plunger thereof will establishv connection between his line enel rthe idle trunlv-line Which ell of the iclle subscribers piangere have heen. Waiting', thus causing' ell idle plungers to again acl vence in unison te e new and ielle sivit position. lt is evident, therefore, that eeeh plunger is subject to only connective openetions on the part of its allotted subscriberi but is subject to only selective eperetions on the part of any other snliserilier in the serie group. Ne subscriber er n use his ivliii'' i e -siviteh7 Without advancing' all et i rlividualswitches in the seine greep te idle switching position, and no subscribe een release his inrliviilnel-switch Wi Aieut causing; the plunger thereof te miteinetiee n' swing' itself into. e posit-ien eerrespenrgling te the sWit'el-iing- 'pesition et that time eee. pied hy all other iclle plringers. Each snlyseriberls infliviclunl-switch. when he is .net Using it, is always ready nucl in Waiting te elese een-- neetion with :u1 idle trunk-line, encl the Celiing subscriber lies but te trip the eirenitclosing;` ineens or" his individuel-switch in order to ceuse the letter te close the :already or orevionslj,7 selected idle trunk-line eenneetion.

It will be seen that the mechanism of the master qWith, or the switch-operating ineehine es it may be called, constructed, for exemple, as shown in Finn 27 constitutes en automatic means or mechanism for selecting iclle talking trunks ahead of the eellswthet is to say, for selectingidle trunks for the calling subscribers. ln this' wey e eoinnion mechanism is provided for selecting the iclle trunks, and the subscribers ere provided with individuel devices for seizing` the preselected idle trunks. l/Vith this arrangement enel) (felling subscriber' merely operates his individuel switeli er device fer the pi rpose et seizing the preseleetecl trunk, and the seine time causes the eoinnien 'trunk-se* leeting mechanism te step orvercl and thereby select e new or different trunk `for the subscriber who inelies the next cell. lt will also he seen that the plnngers Til serve es swinging and enclwise-moveble members for traversing' the series of trunks, enel for engaging; :intl seizing a. preseleetetl idle trunk. Preferably, as shown end eleseii'ihed, these iilnngers or stepliy-step et Itoil Swinging niei'nliers We ere exelueled 'lli talking Qiien without f.

poses e fing l L 'ways ready and in pesitien te etn'neet Btl 'e rnevenient tieni; te another, se that 'when not vin n for talking purposes, li, plunger er swinhing inemljer is in elineinent' with en idle trnnl, enti thus Weit/ing te resp.' .nfl te the calling; subscriber for the purpose oi seizing` snel; trunk. As shown end dese'ihe, tlie said plnngers er swinging step-ley-step en ere'tefl members 74@ ere normally out of e@ gegeinent with the trunk terminals, lont this may also he ineeliied or changed Witheet Ideparting freni breeder purposes et my invention. in tnis weyj stetefl, pre vide e commen mechanism fer selecting idle treillis ahead et the cells, er 'ireviole e plmelity ef reveling inei'nli n traverse the mii line te ininels w 'i in use lier "'h phone sv fiber@ s vitlne. switch" etlapt if" ing' suhseribei te eenneet with e 'i number of treni-z li I` i n swingine; for eonneetien ,Ween and en ne onf' et te-.1nA l` tellcing el.

ing-

lines, n, i een ze ng 'the snbserihers one trnnlehnes, nire laterally ene emlwise nievehl v e plu snliss line with. itlle trnnl, while VLne seiil se'ilteli noi'I in use.

A telephone system eer" girifi0' ing' subserihers line7 :in ir i elletteil te seid line, e n llnes leading' from seirl iv Being* mehle of establish lie-tween the suoseriherls .li olfA seid trunk-lines7 provielef: :illy :intl endwise inovehle pli in pl tien to establish eennee idle in snleline .vliile the finnllserilieils is net in 4l A telephone system eeniprising e en seribers line, e plurality el? erteilt-linees s switching device eenllile olf estelilis ling connection between seiegl snloserilierlsl nml :,iny ene ef seid i'grnnl'ulines. and pi virfleiil with. e titerelly enti end vvise movi plunger iter searching ,line vvnile t snleserihei" het ely :intl

zien witl e enti any e vsubscribers lines, but less in number than to select the next idle trunk-line, each switch the said subscribers lines',xtogether with an individual-swi-tch7 for cach subscribers y line, and means common to all of said subscribers `lines for operating said switches7 `each switch being provided with a laterally' and' endwise movable plunger for establishing connection with any one of said trunklines, always ready and in, position to estab* lish connection with an idle trunk-line while the subscribers line is out of use.

6. A telephone eff/stem comprising a plurality ot subscribers7 lines, a` plurality of 7, A telephone system comprising a4 switch, said switch including a plurality of trunkslinetern'linals, a paii` of subscribers linc-tcrminals` arranged `at opposite sides of said row of trunk-lineterminals, each l'runli-lineterminal consisting; of a pair ot switch-springs, and automaticl means for selecting an idle trunlslinej and a laterally vand endwise movable plunger `for forcing the terminal.springs ot such idle l unlcline into engagement with the said suscribcrs line-terminals.

8, A telephone system comprising a plurality ol subscribers lines. an individualswitch for each subscribers line, each switch provided with a laterally and endwisc movable plunger, a plurality of trunklines less in number than the subscribers lines and each connected with all of said switches, automatic means for enabling any switch when put in use to cause any and all idle plungers to select the next idle trunkline` `each switch when out of use always ready and in position to establish connection between its allotted subscribcis line and a preselected idle trunlrdine. l

Sl. A telephone system comprijinar a plurality olf-subscribeis lines, an inulividuab switch.77 Yfor each subscribers line, each switch provided with a laterally andendwisc movable plungerq a. plurality of' trunklines less in number than the subscribers lines and each connected with all of said switches, and eleetrically-operated auto matic means for enabling each switch when put in use to cause'any and all idle plungers preliminary when not is use always ready and in position to establish connection with a prese lect-ed idle trunk-line.

l0. A telephone system comprising a subscribers line provided with stationary terminals, a plurality of flexible tru11k-lineterminals each adapted to be forced inte contact with said subscriberslineterminals, other subscribers lines having; similar lineterminals, other trunlvline-terminals connected with the same trunk-lines and associated with said other subscribers line-ter minals, a circuit-closing plunger for each subseribers llne,

` rality of subscribers7 lines, a plurality of and automatic mea-ns' `whereby each plunger 1s3 when not 1n use always ready and 1n position to establish trunk lines less in number than the said subscribers lines, an individual switch for-each subscribers line, each trunk line being connected with all of said switches, the said cuit-closing device when put in'use causes any and all idle devices to simultaneously select an idle trunk line, each said device ywhen in use always ready and in position' to establish connection between itsfallotted subscribers lines and the pre-selected one of said trunk lines.

12. A telephone systeml comprising a subscribers line, a subscribers calling device, automatic switching' means adapted to respond to the first electrical impulse produced by the operation of said calling device, and additional switching meansl also adapted to respond to said liirst impulse and to perform .switching operations corresponding to all digits of the called number in response to additional electrical impulses produced by the said calling device subsequent to the operation of said preliminary automatic switching means.

13. A telephone system comprising a subscribers line, a subscribers calling device, automatic switching1 means adapted to perform a trunking operatior'i in `responsev to the first electrical impulse produced by the operation of said device in calling the desired number9 and a stepby-step selective ino y lll'i switching machine adapted to perform an a plu-5 

